1. Field of the Invention
The present invention relates to new alpha-aminooxy isovalerates, their use as insecticides and to insecticidal formulations containing these new compounds.
2. Summary of the Invention
The present invention is directed to new alpha-aminooxy isovalerates of the formula I ##STR2## wherein X is a halogen atom; n is 0 or 1; R.sup.1 is a hydrogen atom or an alkyl group containing from 1 to 6 carbon atoms; and R.sup.2 is an alkyl or an alkenyl group containing up to 6 carbon atoms or a phenyl group optionally substituted by one or more substituents selected from a halogen atom or an alkyl group containing from 1 to 4 carbon atoms optionally substituted by one or more halogen atoms or by a methylenedioxy group. These new compounds are useful as insecticides.
Non-limiting embodiments of species within the scope of the invention include:
Butanoic acid, 3-methyl-2-(((1-(4-bromophenyl)ethylidene)amino)oxy)-, cyano(4-fluoro-3-phenoxyphenyl)methyl ester, PA0 Butanoic acid, 3-methyl-2-(((1-(3-(trifluoromethyl)phenyl)ethylidene)amino)oxy)-, cyano(2-methyl-3-phenoxyphenyl)methyl ester.
The halogen atoms used in Formula I include chlorine, fluorine and bromine.
In the Compounds of the Invention, R.sup.1 is preferably a hydrogen atom or a methyl group and R.sup.2 is preferably a methyl group, a 2-methylpropenyl group or a phenyl group substituted by one or two groups selected from chlorine, fluorine, methyl or trifluoromethyl or by methylenedioxy.
In one embodiment of the Invention, R.sup.1 is a hydrogen atom and R.sup.2 is a phenyl group substituted by chlorine, trifluoromethyl or methylenedioxy. For example, R.sup.2 is 4-chlorophenyl, 2-chlorophenyl, 3,4-methylenedioxyphenyl, 3-(trifluoromethyl)phenyl or the like.
In another embodiment of the Invention, R.sup.1 is a methyl group and R.sup.2 is 2-methylpropenyl, 4-chlorophenyl, 3,4-methylenedioxyphenyl and the like.
In another embodiment of the Invention, n is 1 and X is a fluorine at the 4-position or n is 0.
The Compounds of the Invention can exhibit geometrical and optical isomerism. The present invention includes all the biologically active compounds of Formula I of the invention and the useful intermediates and, thus includes racemates and various geometric and/or optically-active isomers or mixtures enriched in such isomer forms which may be directly synthesized, resolved or mixed together. The various geometrical and optical isomers of the compounds of Formula I may have different biological activity.
The Compounds of Formula I of the Invention are prepared by conventional esterification procedures known in the art. For example, an alkali metal (potassium) salt of the alpha-aminooxy isovaleric acid in an inert solvent (e.g., acetonitrile) is treated with an alpha-bromo-3-phenoxybenzeneacetonitrile.
The alpha-aminooxy isovaleric acids used as intermediates to the esters of Formula I are prepared by forming the alkali metal salt of an oxime with alkali metal hydroxide in an inert solvent (e.g. toluene) in the presence of a catalyst (including onium catalysts) with azeotropic distillation of the water formed. After the water is removed an alkyl, 2-bromoisovalerate is added and the reaction mixture is refluxed, often for 24-48 hours. The reaction mixture is filtered to remove the salts prior to distillation in a Kugelrohr apparatus. The corresponding carboxylic acids are prepared via alkaline hydrolysis in a ternary mixture of ethanol, tetrahydrofuran and water.
The alpha-aminooxy isovaleric acids are also disclosed and claimed in applicant's concurrently filed U.S. patent application, Ser. No. 662,117.
The oximes utilized in making the acids and alkyl esters intermediates of this invention were prepared from the corresponding oxo compound and hydroxylamine hydrochloride via well known methods, e.g., Vogel, A. I., Practical Organic Chemistry, Wiley and Sons, 1966, p. 343.
The alpha-cyano-3-phenoxybenzyl alcohols and their reactive derivatives are known in the art, e.g., from U.S. Pat. Nos. 3,835,176, 4,218,469, 4,276,306 and the like. Chiral forms of these alcohols and their preparation are also known as in U.S. Pat. No. 4,273,727 and the like. In general, esters of these alcohols have previously been found to have their highest insecticidal activity when the alcohol is in the S-optical configuration. Thus, the preferred esters of the Invention are those in which the alcohol moiety is in the R,S-racemic or S-optical configuration.